Wake Up Seeds!!!* Ms. Gormus Agriscience I This presentation is from Virginia Tech and has not been edited by the Georgia Curriculum Office. *All sides adapted from Introductory Horticulture, 1991.

What is propagation? Basic reproduction of plants Sexual process Asexual process Propagation is basically the reproduction of plants. There are two main processes: sexual and asexual. Today we will be covering the sexual process and more specifically seeds. The asexual process covers cuttings which we will study next time.

Seeds Sexual reproduction process Seeds produced from joining of pollen and egg Self-pollination Cross-pollination Seeds are a form of sexual reproduction. Seeds are produced from joining the pollen and the egg. The pollen is the male sex cell and the egg is the female sex cell. If the egg and the pollen comes from the same plant it is called self-pollination. If the egg and the pollen come from two different plants it is called cross-pollination.

Composition of Seeds Seed Coat Endosperm Embryo The three components of the seed are the seed coat, endosperm, and embryo. We will talk about each of these in turn. Draw and label “composition of a seed” picture on page 63 in text (Introductory Horticulture)

Seed Coat Outside Covering Protection Transportation The seed coat is the outside covering of the seed. It protects the embryonic plant. Because there is a seed coat, the seeds can be transported and stored for long periods of time without damaging the embryo. Refer to drawing on the board when discussing this plant part.

Endosperm Food storage Nourishment during germination **Ask: What is the function of the seed endosperm??? Have students think about the diagram and then give any answers to the instructor. Correct answers would be: food source, or food storage. Uncover the slide and then discuss the following The endosperm’s main purpose is to provide food for the embryonic plant during germination. As you can see on the diagram, there is a lot of food saved for the embryo since germination requires lots of energy for the seed to “wake up”

Embryo New plant Result of fertilization Grows roots and seed leaves The embryo is the new plant that is a result of fertilization from the pollen and egg as discussed earlier. The embryo, under the right conditions will extend roots and seed leaves to form a new plant.

Propagation from seeds Quick and economical Proper environmental and cultural conditions Temperature Moisture Light Media Seeds germinate relatively quickly and are inexpensive. However, proper environmental and cultural conditions must be present for maximum seed germination. The temperature should be relatively warm with no threat of frost. When would the correct time be to plant outside in Virginia??? Late April or Early May if it is warm The soil should be kept relatively moist but do not over water as the plant will drown. The seeds should be exposed to bright light for best results. The media should be light and not heavily fertilized. You may add fertilizer later but at this stage too many chemicals could damage the germinating seed.

Advantages of Seed Propagation Quality Primed Develop quickly Less cost So why choose seeds over other methods of propagation? Well, there are several advantages. Over time, many attempts have been made to improve seed quality. Seeds are now sorted by weight and the uniformity of a packet of seeds has greatly improved. This means that the seeds will most likely come up at the same time. Secondly, the seeds are primed or enhanced so the growth enzymes become active and are quicker to start under the right conditions. **What are those right conditions as we just discussed???*** Temperature—no threat of frost Moisture—moist soil but not too wet Light—bright sunlight is best Media—good mix and also needs to be light enough for the seeds to break through Seeds also develop more quickly than other types of propagation (one example would be cuttings). Germination for seeds range from about 3 to 10 days, whereas cuttings could take weeks for a small amount of root to form. Seeds are also inexpensive. A pack of seeds usually ranges from $.10 to $.80.

Disadvantages of Seed Propagation Small, some hard to plant Plant too thick Age of seeds Some disadvantages of seed propagation are that some seeds are very small and may be hard to plant. Usually these seeds are planted too thick in the rows or beds and many seeds get choked out. Another disadvantage could be the age of seeds. After a certain time, seeds are not as viable as they once were. Therefore, if your seeds have been sitting around a long time, they may not have a very high germination rate.

A quick review… What is plant propagation? What part of a seed provides protection for the embryo? What are the four environmental conditions that must be monitored when propagating seeds? What are some advantages of seeds? What are some disadvantages of seeds? Basically reproducing plants. Seed coat Media, light, moisture, and temperature Quality, primed, develop quickly, less cost Small, some hard to plant, plant too thick, age

Now a practical exercise… Move students to the lab to demonstrate preparation of seedbeds and correct propagating procedures